Electric furnace.



No. 68u07..

' Patent-ed Aug. 2i), Ei. A. H. CWLES.

ELECTRIC FURNCE.

{Applicaton led Nov. 24, 1899. 'Renewed July 22, 1901.)

(No Model.)

Y @wf @i Stomme-13 Witwe/.aow @if f? passes practically ges-tight. @neof the eleotrode'terminsls is attached to the outer instelcasinuor-jeelret d at M und the other io the rod-4C2 at N. Although notstrictly essentini,

' prefer to connect un inlet-pipe g to the upper. part ofthe pipe il,through which; lii' found necessury or desirable, u, snsli quentity ofhydrocarbon or reducing gus or forming liquid muy he passed into theupper part of--the pipe il, which will prevent any small amount ofsodium from passing up es vapor around the. electrode C2, A suiicieutamount of the hydrocurbon ges een be 'ndy mitted to maintain s slightescape thereof .d swu around the said electrode.,

v For feedin the' ore chargeb to the furnace c hopper El.,

, haiti-ing: vnlires m, is lccsied at the top et the Viu'rnuce, and theletter is ,provided with u.

safety-valve. G and u pressure-gege P. One of the cables .forthe-electric current is attached to the outer wall of the wetter-jacketd utlany desired point, and the course of the current is Jtrom thecircuit-cable connected with the electrode C throughthe charge, the.walls of the fu mace-chamber, 'the stay-blocks, and -the'cnsing orWater-jacket' to the et er circuit-terminl. l

As here'iubeore suited, this furnace is especilly applicable to thereduction of the class of compounds of which ulurninate oil soda.(NalAlO-i) 'is u type, yet it is quite -as applicable-to other classesot reductions 'where salts ire to be electrolized,` and Wish it tobe'distinctly understood that its application is unlimited. y, Takingalu minste of sode es u typical comlpound, the operation of the furnaceis as fol Y lows: Take a mixture -of aluminste of sodo with coke' orcarbon'iir any form, forming such mixture either by mixing the crushed,ground, or granulated materials or by forming a msssof sodio alnminatesaturated with e hydrocnrbon'end baked, and, if yneed be, crushed, or bymixing the sluxninute of sode with carbon and coal-terror pitch orequivalent carbonaceous matter, it being desirable that the ore chargeshould not be too powdery in consistence und it being also preferable,except when curbids are being formed,-

'tbat no excess of curboniaboye the amount 'necessary for the reductionshould be empioyed, since such excess will accumulate in the furnacesndmuy need to be removed. The charge mixture is fed through the hopperinto the furnace in successive portion, regulated according to .thejudgment ofthe operator by the temperature and pressure of the furnace.1f the ore charge is fed too slowly, the furnace will become too holt,which will be indicated to the operator not only by 1 the noticeableincrease of temperature of the -furnace and the water discharging fromthe water-jacket, but also by the diminished amount of carbonio oxidpassing ci?. If ythe charge is 'fed teo fast, there willl accumulate inthe furnace s muss of fused unredueed alu-- mina, which will be.observedin topping cid from time to time the contents of the fu rnuce.As .the ore charge is fed to the; furnace the high temperature causesthe sodium to distil.

off rapidly along with the carbonio oxid produced by the reduction oftheoxid of aluminium. These gaseous products passing through 'the porouscarbon Walls of the' furnace into the condenser R, formed between theseid sodium is liqueiied; but by ineens of- 'the wster-jacket it is keptbelow the tesuperstitirev (red heat) et which sodium is volatile. The

interior of the furnace is mnintenedut n, very' high temperature,reaching incendesceuce on the innery su rface et the carbon wallund-dre-A creasing c adull red heet et the iron casing,`

By this means sodium is'prevented from con.-

densing in the furnace und any possibility ofv short-circuitingarising-from condensed sodium condensing on 'the inner walls of thefurnece at the junction of the cover und body- Wall or elsewhereis'prevented, although such short-circuiting could not occur to unextent to materially affect the operation, since the sodium in such easewould be instantly vol'atilized by theh'est of the current shoutedthrough it.

' The gases evolved in the furnace during the operation create a,pressure within the furnace, which will be indicated to the operv sterby the pressure-gage l), and although' ICO there is very little, if any,danger of the pressure reaching a. point where any injury totheapparatus could occur therefrom, yet the possibility thereof is fullyobvietedby providing the safety-valve O. This pressure in the 'fur- IIbnace materially assists in driving through the' porous carbon wall ofthe furnace the volw-- /tilized sodium vapor and the gases evolved inthe operation.

f The oxid of aluminium left by driving-off i i the sodium from thelaluminste is acted upon and reduced by the'earbon, the reaction yieldingcarbonio oxid and carbid of aluminium, the carbonio oxid passing throughtrie-'walls of the furnace and the aluminium cng'id res` mainiug' andaccumulating in the bdttom of the furnace, from which it is st suithleintervals drawn ed through the ope'ningllfv By adding through .the orechargeencther wise in reducing it in the furnsce Ve/,finets'l lessVolatile than sodium-as, for instance, iron,

copper, 'or tin-un a'lloy'of the reduced alu-1 miniem with ysuch metalis obtained., Eurther, by adding'in the same manner s volatile metal,such as zinc, there will be obtained in the condenser an alloy-of sodiumwith such othervolatile instel, all of such operations,

reactions, and reductions being successfully Acarried out by thisfurnace.

It is advisable to heat up the furnace to a high temperature beforeadding the ore to be reduced, which is readilydone by puttingin aquantity of granular carbon in the bottom `of the furnace to save thecarbon lining of the furnace and allowing the arc to play lthereon, oneadvantage of which is that by previously raising the furnace to atemperature so high that the ore willreduce rapidly a more perfectoperation is secured at more economical expense. The charge fed into thefurnace should be proportionate to the .electrical ener y` delivered tothe furnace,

the best resultsV eing obtained when the electric current and the feedof ore are so proportioned that the ore is reduced as fast as fedi'n-and the process of reduction conducted in a substantially continuousmanner.

By mixing sodium compounds with calcium compounds and the properproportion of carbon there may be obtained sodium, volatilized andcondensed in the' condenser, and calcium carbid remaining inthe furnace.

I do not limit myself to a water or airjacket .surrounding the furnace,though the use of -such enables the maintaining of a better controloverthe process that may be carried on in this furnace; but such jacketmay b e dispensed with and the atmosphere of the room or othercompartment containing the furnace may be kept in condition tofcause asufficient cooling surface with a properly-regulated delivery ofelectric energy to the furnace.

Having described my invention, what I -1.- An electric furnace having awall permeable to vapors and gases,and a condensingchamber outside ofsaid permeable wall.

2; An electric furnace havinga closed furnace-chamber the wallsof whichare permeable to vapors and gases, and a condensng-4 i chamber outsideof the said walls.

3. Au electric furnace having furnace,

chamber walls and hearth permeable to vasurrounding the exterior of saidwalls andA hearth. I

4. The combination, with a. porous furnacechamber wall permeable tovapors and gases, of a water-jacket surrounding the exterior of saidwall to form a condensing-chamber be- V `the jacket and the walls.

6.' In an electric furnace the combinatiom' with the porous carbonforming'the furnacechamber and enabling the gases to pass thereu from tothe'exterior surface of the-chamber, of a cooling-jacket covering theexterior of said chamber, anda condensing space or' chamber between theterior surface.

7. The combinatiomwith the porous-walledf urnace-chamber having'acondensing-chamjacket and the said exber surrounding it, and acompactedl carbon' top provided with a Afeed hopper, of a gas-4 tightpipe attached, t'o the said top, and the electrode passing through saidtop and working in said pipe. g

In witness-whereof Iihereunto set myA hand in thepresence of twowitnesses ALFRED H. CoWLEs.A

Witnesses:

EUGENE L. PoMERoY,

NELLIE WILLs WELcH.

